I had a similar (probably the same) problem: trying to run "esd" would yield a message like you (Wladston) were getting when trying to run aplay. Here's how I fixed it:
chris@chris-desktop:~$ asoundconf list
Names of available sound cards:
M5455
M44
chris@chris-desktop:~$ asoundconf set-default-card M5455
chris@chris-desktop:~$ esd &

Of course, I don't know if esd is going to be running after I reboot again...